1. Field of the Invention
The present invention relates to towing devices and more particularly relates to a towing apparatus providing interchangeable trailer balls which are removed by means of a concealed actuating pin recessed within the assembly so as to prevent inadvertent disassembly and shield working parts from weather. Even more particularly, the present invention relates to an improved interchangeable trailer ball apparatus in which a concealed, shielded release mechanism remains attached to the vehicle bumper and interchangeable integral trailer balls interchange therewith, shielding and covering the release mechanism upon assembly.
2. General Background
A common device for towing trailers uses a ball which is mounted on the bumper or draw works of a vehicle. The trailer ball forms a ball and socket coupling with a trailer. Typically, the socket portion is on the trailer tongue. Normally the trailer provides some sort of adjustable coupling as part of the tongue which allows the socket to slip over the ball and thereafter the coupling is closed or secured so that the socket cannot be removed from the ball. An articulating ball and socket coupling then allows movement of the trailer with respect to the vehicle as typically occurs during towing.
The size of these ball and socket connections are usually standardized and measured or specified in terms of trailer ball diameter. Unfortunately, trailer ball diameters are not always the same size for a given trailer. For example, there can be a plurality of different diameters which an individual might be required to use for towing various trailers. Typical diameters of trailer balls are, for example: 17/8 inches, 2 inches, 21/4 inches, and 2 5/16 inches.
Often times a user may leave a trailer ball on his bumper for a long period of time and forget the particular size and possibly be inconvenienced or stranded when a trailer needs to be towed which is of a size that doesn't fit the particular trailer ball. One solution which is inefficient, time consuming, and bothersome if implemented is to keep a large wrench in the trunk or other storage compartment of the vehicle to manually interchange a plurality of trailer balls of varying sizes. This process often requires the user to dirty his hands and/or clothes with rust, dirt, grease, and the like in order to change the ball. This problem is complicated of course in poor weather conditions such as snow or rain. Often times the trailer ball assembly cannot be removed with a wrench because the thread and nut connection has become rusted and/or corroded and cannot be disassembled with ordinary manual force. It is to this general problem that the present invention is addressed.
Several trailer "hitch" connections have been patented. Some of these devices purport to provide interchangeable balls of varying diameter.
For example, the Hoogenbosch U.S. Pat. No. 4,201,400 issued on May 6, 1980 provides a towing device comprising a towball and latching means releaseably operable to, in use, secure the towball to the drawbar of a vehicle. An upper actuating button penetrates the upper surface of the ball. The entire actuating mechanism must be provided with each and every interchangeable ball. The upper actuating button is undesirable because water from rain can enter the mechanism.
In U.S. Pat. No. 2,297,182 issued to D. S. Weiss on Sept. 29, 1942 entitled "Trailer Coupling" there is provided a ball-and-socket coupling with permanently engaged ball and socket elements and a protected and easily lubricated wearing surface. Also provided is means to compensate wear in the various parts.
In U.S. Pat. No. 2,189,710 entitled "Hitching Device for Trailers", issued on Feb. 6, 1940 to L. H. Draeger there is provided a hitch element on which a ball of novel form is positioned for cooperation with a two part socket carried by another hitch element; the socket being so designed and arranged as to include one main integral section which encloses more than a half of the spherical ball structure so that the stresses and stains are primarily on the sold mass, and a locking portion of the socket which functions for retaining the ball in its seat in the main section. Other features include the elongated shape of the socket seat for the ball permitting its disengagement after loosening of the locking element, the structure of the socket locking element, the adjusting bolt, and the locking means for the latter.
In U.S. Pat. No. 2,438,749 issued on Mar. 30, 1948 to Paul Harrer entitled "Hitch", there is provided a trailer hitch comprising a socket member provided with peripheral lugs and adapted to receive a ball element and a retainer member formed for cooperation with the lugs and with the ball element for retaining the element within the socket member when said members are interlocked upon partial rotation of one relative to the other.
In British Pat. No. 644,159 issued to Henry Billington, there is seen couplings for trailer vehicles of the kind in which the drawbar of the trailer vehicle has secured thereto a ball member and a socket member which are permanently in engagement; the ball member being provided with a shank having a tapered portion, the lower end of the shank being adapted to be engaged by a member carried by the drawbar of the tractor vehicle whereby the tapered portion of the shank can be drawn into a tapered hole in the tractor drawbar.
In the Church patent (U.S. Pat. No. 3,630,546), there is provided a compound male coupling member for a ball-and-socket-type hitch, and wherein the member is composed of selectively exchangeable components coacting to form hitch balls each having a different diameter. The hitch ball is formed of a pair of identical semispherical members as shown in FIG. 2 of the drawings. The upper end of the bolt is adapted to be encased in the two semispherical members. The assembled structure is held together by a conventional nut which is releaseably threaded onto threads.
3. General Discussion of the Present Invention
The present invention solves these prior art problems and shortcomings by providing an interchangeable trailer ball assembly which uses an elongated bumper pin having an internal longitudinal bore with at least one lateral bore extending from the longitudinal bore at generally right angles thereto. The lateral bore both intersects the longitudinal bore and is exposed at the surface of the bumper pin. The bumper pin can be attached to the bumper or draw works of a vehicle by means of for example a thread and nut connection. An annular shoulder on the bumper pin completes the assembly of the bumper pin to the draw works or bumper. At least one locking element is movably mounted within the bumper pin in each lateral bore between retracted and projected positions. Disposed slideably in the longitudinal bore is an actuating rod which is moved in a slideable fashion between extreme positions which cooperate with the locking element to produce the aforementioned retracted and projected positions of the locking elements. Interchangeable trailer balls are attachable to the bumper pin one at a time as selected. Each trailer ball is integral and provides a closed end bore receptive of the bumper pin. A recess communicating with the closed end bore of the trailer ball can be provided for forming a connection with the locking element to secure the trailer ball upon the bumper pin.
In the preferred embodiment, the exterior surface of each trailer ball is integral and uninterrupted to prevent the entry of rain and/or dirt which might damage working parts. A feature of the present invention is that the mechanism for releasing the trailer ball is contained entirely within the bumper pin which remains permanently on the bumper of the vehicle so that a one piece integral trailer ball can be cheaply and inexpensively manufactured to fit upon the bumper pin. This produces a dependable trailer ball apparatus which is simple to use, easy to maintain, and inexpensive to manufacture.
Another feature of the present invention is that the actuating rod is entirely disposed internally of the assembly so that it cannot be inadvertently actuated or tripped. Thus, the present invention provides an interchangeable trailer ball apparatus which is safe. In the preferred embodiment, movement of the actuating rod is effected by using a tool such as an elongated shaft such as a large nail for example to move the actuating pin. This provides a tamper resistant and child-proof assembly which discourages inadvertent or undesired release of the ball from the bumper pin.